I've recently been having problems similar to this, try doing the following:
1. Make sure you have the latest patches & SPK for SQL
2. Defrag your drives to stop memory related issues
3. Set the tempdb DB properties to use Recovery (FULL) not simple
NB>You can change all of them to Full if you want however, DO NOT change "master" to FULL! Anyway at least that is what M$ says...
4. In maintenance plan jobs make sure you specify the location and add -SupportComputedColumn'
i.e. EXECUTE master.dbo.xp_sqlmaint N'-S Servername\SQLServername -PlanIDXXXXXXXXXXXXXXXX.....-SupportComputedColumn'
5. Use a seperate Maintenance plan for "transaction backup logs" and don't include the "masterDB" as that doesn't work.
Double check
Recovery model of your databases should be FULL
